Transfer Rate; Data Sampling Method - Toshiba TLCS-870/C Series Manual

11.4 Transfer Rate

The baud rate of UART is set of UARTCR1<BRG>. The example of the baud rate are shown as follows.
Table 11-1 Transfer Rate (Example)
BRG
000
001
010
011
100
101
When TC5 is used as the UART transfer rate (when UARTCR1<BRG> = "110"), the transfer clock and transfer
rate are determined as follows:
Transfer clock [Hz] = TC5 source clock [Hz] / TTREG5 setting value
Transfer Rate [baud] = Transfer clock [Hz] / 16

11.5 Data Sampling Method

The UART receiver keeps sampling input using the clock selected by UARTCR1<BRG> until a start bit is
detected in RXD pin input. RT clock starts detecting "L" level of the RXD pin. Once a start bit is detected, the start
bit, data bits, stop bit(s), and parity bit are sampled at three times of RT7, RT8, and RT9 during one receiver clock
interval (RT clock). (RT0 is the position where the bit supposedly starts.) Bit is determined according to majority
rule (The data are the same twice or more out of three samplings).
RXD pin
RT clock
Internal receive data
RXD pin
RT clock
Internal receive data
16 MHz
76800 [baud]
38400
19200
9600
4800
2400
Start bit
RT0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0
Start bit
(a) Without noise rejection circuit
Start bit
RT0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0
Start bit
(b) With noise rejection circuit
Figure 11-4 Data Sampling Method
Page 125
Source Clock
8 MHz
38400 [baud] 19200 [baud]
19200
9600
4800
2400
1200
Bit 0
1 2 3
Bit 0
Bit 0
1 2 3
Bit 0
TMP86PM29BUG
4 MHz
9600
4800
2400
1200
600
4 5 6 7 8 9 10 11
4 5 6 7 8 9 10 11